1. Field of the Invention
The present invention relates to a nonvolatile semiconductor device arranged with a memory cell array having a plurality of memory cells which can electrically reprogram data.
2. Description of the Related Art
As described in Japanese Laid Open Patent 2003-233992, a device which can electrically reprogram a plurality of data which is stored in a memory cell array as a nonvolatile semiconductor memory device, is proposed. In this type of nonvolatile semiconductor memory device, a plurality of data which is read from a memory cell array is once transferred to an I/O buffer after having been once stored in a page buffer circuit.
Here, in this type of nonvolatile semiconductor memory device, for example, there is a nonvolatile semiconductor memory device which is arranged with both a function which transfers eight bits as a single unit of data (eight bit data) to an I/O buffer device (eight bit data transfer function) after reading the data from a memory cell array and transferring the data to a page buffer circuit, and a function which transfers sixteen bits as a single unit of data (sixteen bit data) to an I/O buffer device (sixteen bit data transfer function) after reading the data from a memory cell array and transferring the data to a page buffer circuit. While a usual construction of an I/O is eight I/O, one part has a sixteen I/O construction, therefore, there is a nonvolatile semiconductor memory device having both the functions so that it can be managed within the same chip regardless of I/O construction.
In a nonvolatile semiconductor memory device which is arranged with both an eight bit data transfer function and a sixteen bit data transfer function, data is transferred with the operation of a sixteen bit data transfer function as a standard. Therefore, in this type of nonvolatile semiconductor memory device, sixteen bits of data is transferred in one transfer cycle period in the case where this data is sixteen bit data. However, in the case where this data is eight bit data, two eight bits of data can not be transferred in one transfer cycle period, only one eight bit data can be transferred. Consequently, there is a problem whereby data can not be transferred at high speed.